In Re N-500L Cases, 517 F. Supp. 825 (D.P.R. 1981) ("The Court finds that the pilot of N-500L was responsible, in the VFR flight conditions which existed on the night of the accident, to visualize and to avoid wake turbulence of EAL 75. By continuing into the flight path of EAL 75 the pilot of N-500L was negligent and this negligence was a proximate cause of the crash.").
Bauschspies, James S. and William E. Simpson, "Research and Technology Program Perspectives for General Aviation and Commuter Aircraft", NASA Contract NASW-3554 for NASA, Sept. 1982, N83-17454#. Retrieved: 18 Dec. 2014. (In particular, see: Table 2.4 "COMMUTER CARGO FLEET IN 1981 - TOP TEN AIRCRAFT MODELS - NUMBER IN FLEET," which notes Beech 18 units are more than the next two aircraft combined (Convair 500/680 and Douglas DC-3), and more than the next three general aviation aircraft combined.
Croce v. Bromley Corporation, 623 F.2d 1084 (5th Cir. 1980) ("The plaintiffs' expert medical witness testified at length that spatial disorientation resulting from the pilot's taking off into a "black hole" was the cause of the crash. See n.12, supra. This theory was buttressed by the testimony of Asher Vandenberg, a commercial, multiengine pilot with instrument ratings.").